Cone drill bits for drilling roof. Any thoughts?

[biosurf]

So... to drill the hole in the roof for the CB antenna I was planning on using a small drill bit then stepping up the size. However I have also seen these cone drill bits.

http://www.screwfix.com/prods/45562/...-Drill-Bit-Set

Any experience of using them? It seems that they would be easier to use than drilling ever larger holes but not having used either method before I thought I would ask what the consensus is as to what the better option would be.

Shame I don't have anything to practice on first but then that would take away that teeny bit of buttock clenching excitement!


EDIT: I am taking an old fridge to the dump tomorrow... maybe I can attack that first

[tonupteabag]

it might be worth getting the stepped type cone as it will be easier to get the correct diameter without any hassle rather than the plain cone and you keep having to stop and measure your hole size

[BUSHWHACKER]

Get yourself a vernier caliper, measure the diameter of the part you want to fit into a hole, and use a hole saw.
I don't like using large drill bits on thin metal sheet like car bodywork, there's a risk of dents or creases or snatching when the drill bit suddenly breaks through.

[biosurf]

Cool thanks Vince. Ill do that.

[Apache]

I think I made 9 holes in the roof of my truck. I just used a couple of new drill bits and a couple of good quality files. The roof is very thin and easy to drill. You wont have any problems.